Extension cords typically have a plug at one end and one or more sockets at the other. Extension cords effectively "extend" other electrical cords, such as appliance cords.
Conventional extension cords are limited since they provide sockets only at the end of the cord. Many household and office spaces have multiple electric appliances and equipment. An office desk may have a computer, monitor, printer and light, while a family room may have a television, telephone, light, and stereo. In a room where the appliances are spread apart, a single extension cord having sockets only at one location cannot service all the appliances. For these applications, a number of extension cords is often required. This can create an unsightly and sometimes dangerous situation.